Colorant concentrates for thermoplastic biofiber composites

ABSTRACT

Color concentrates for thermoplastic biofiber composites are disclosed. The concentrates employ three factors to achieve concentrated delivery of color to the processing machine and excellent and substantially uniform dispersion of color in the processing machine: melt flow of the concentrate exceeding at least 4 g/10 min. using ASTM D-1238; pellet size of the concentrate such that at least 50 pellets weigh less than one gram; and weight percent of the colorant ingredients in the concentrate exceeding at least 30 weight percent.

CLAIM OF PRIORITY

This application claims priority from U.S. Provisional PatentApplication Ser. No. 60/864,238 bearing Attorney Docket Number 1200624Rand filed on Nov. 3, 2006, which is incorporated by reference.

FIELD OF THE INVENTION

This invention relates to colorant concentrates useful for makingthermoplastic biofiber composites appear to be naturally-colored orstained wood.

BACKGROUND OF THE INVENTION

Plastic has taken the place of other materials in a variety ofindustries. In the packaging industry, plastic has replaced glass tominimize breakage, reduce weight, and reduce energy consumed inmanufacturing and transport. In other industries, plastic has replacedmetal to minimize corrosion, reduce weight, and provide color-in-bulkproducts.

Recently, plastic has begun to replace wood in building materials wherethe wood is susceptible to rotting, warping, or discoloration. Theadvent of thermoplastic biofiber composites has made outdoor decks,porches, railings and stairways more durable. With structural issuesresolved, the next key factor is making the plastic composite look likenaturally-colored or stained wood.

Much like any assembly line, modules of ingredients come together at afinal article formation station. For example, an extruder for deckplanks might have as ingredients the thermoplastic resin, wood fiber orwood flour, and one or more “masterbatches” of additives.

These masterbatches are mixtures of a plastic resin and specialized,expensive additives, with the resin serving as a carrier for theadditive. The most common specialized, expensive additive is colorant.

Pellet-based concentrates for colorant applications have be used at highdilution or “letdown” ratios to achieve good color distribution.

As with any modern manufacturing facility, production runs ofthermoplastic composites made into final articles need to be veryefficient. In the scale-up of production runs for one quantity of finalproduct, the amount and choice of ingredients in the colorantconcentrate can be quite different from the amount and choice ofingredients in the colorant concentrate for production runs for adifferent quantity of that same product. In other words, no two colorantconcentrates are likely to be the same, because of the need to matchcolor precisely, but there are significant issues in attempting to mix acolorant concentrate into a thermoplastic biofiber compound to makesimulated wood products.

SUMMARY OF THE INVENTION

What the art needs is a colorant concentrate suitable for a productionrun that is most efficient according to the quantity of coloredthermoplastic biofiber composite needed for inventory and just-in-timeprocessing, without sacrificing the appearance of the final simulatedwood product.

The present invention solves this problem in the art by combining threefactors to achieve concentrated delivery of color to the processingmachine and excellent and substantially uniform dispersion of color inthe processing machine:

(a) melt flow of the concentrate exceeding at least 4 g/10 min. usingASTM D-1238;

(b) pellet size of the concentrate such that at least 50 pellets weighless than one gram; and

(c) weight percent of the colorant ingredients in the concentrateexceeding at least 30 weight percent.

The combination of these three factors has been found to provideexcellent color dispersion in the making of thermoplastic biofibercomposites to form simulated wood articles.

Highly-filled colorant concentrates are fragile items. If there is notenough carrier resin to bind together the colorant particles, then thecolor distribution of the final product is totally unsatisfactoryresulting in waste. The same wasted effort and material occurs if thecarrier resin does not have the appropriate melt flow characteristics toadequately disperse within the melt-mixing apparatus, such as anextruder or a molding machine. If the pellets are even conventionalsize, e.g., 40 pellets per gram, there is the possibility that there isnot sufficient surface area per pellet to adequately dispersehighly-filled color concentrates.

Thus, one aspect of the invention is a highly-filled colorantconcentrate for a thermoplastic biofiber composite, comprising: pelletscomprising carrier resin and colorant, wherein (a) melt flow index ofthe concentrate exceeding at least 4 g/10 min. using ASTM D-1238; (b)size of the pellets results in at least 50 pellets having a total massof less than one gram; and (c) weight percent of colorant exceeds atleast 30 weight percent of the weight of the concentrate.

“Colorant” means dyes or pigments.

EMBODIMENTS OF THE INVENTION Carrier Resin

Any thermoplastic resin that is compatible or miscible with thethermoplastic of the thermoplastic biofiber composite can be selected toserve as the carrier resin for the concentrates of the presentinvention.

Non-limiting examples of such thermoplastic resins include polyolefins,polyamides, styrenics, polyesters, acrylics, polycarbonates, and othersconventionally used as carrier resins for colorant concentrate productsand blends thereof, with olefins being preferred because of the ubiquityof polyolefin-based thermoplastic biofiber composites. Of the olefins,low-density polyethylene (LD-PE), linear-low density polyethylene(LLD-PE), and polypropylene (PP) are particularly preferred.

The resin can have any melt flow index value sufficient to cause thecolorant concentrate to have a minimum melt flow index of at least 4g/10 min. using ASTM D-1238 (which is measured using a weight of 2.16 kgand a temperature of 190° C. for PE and 230° C. for PP). Desirably, theresin should have a melt flow index value sufficient to cause thecolorant concentrate to have a minimum melt flow index of at least 6g/10 min. Preferably, the resin should have a melt flow index valuesufficient to cause the colorant concentrate to have a minimum melt flowindex of at least 8 g/10 min.

Within these considerations and recognizing that all ingredients of theconcentrate contribute to melt flow, the resins, or blends of them,useful in the present invention have a melt flow index of at least 20g/10 min., desirably at least about 30 g/10 min., and preferably atleast about 50 g/min. and even more preferably in excess of 100 g/min.if such resins are reasonable in cost and available.

Non-limiting examples of commercially available thermoplastic resinshaving melt flow indices within the acceptable ranges include LDPE fromDow Chemical, LLDPE from CP Chem and Dow Chemical, and PP from Baselland Huntsman.

Colorant

As explained above, colorant can be a pigment, a dye, a combination ofpigments, a combination of dyes, a combination of pigments and dye, acombination of pigment and dyes, or a combination of pigments and dyes.The choice of colorants depends on the ultimate color desired by thedesigner for the plastic article.

For thermoplastic biofiber composites intended to simulate theappearance of wood while providing the durability of thermoplasticcompounds, the importance of colorants in outdoor usage is a significantfactor to the selection of colorant or colorant combinations. Long-termaging studies of articles made from compounds that include colorantconcentrates of the present invention are needed to assure that thedesired color remains for the desired duration and otherwise ages wellas would the wood it is intending to simulate. Therefore, one skilled inthe art without undue experimentation can pick and choose colorants fromthose listed below, and others known in the industry, in order to findboth an initial color match and a suitably durable coloration for thesimulated wood product.

While most circumstances of usage for thermoplastic biofiber compositesare likely to be exterior building materials, exposed to theenvironmental elements of their locations, it is also possible that suchcomposites will be employed within interior locations where climate canbe controlled. Whereas inorganic pigments might be preferred for theexterior locations, both organic pigments and dyes might be useful forthe interior locations, according to the choices of the skilled polymerchemist, architect, and others.

The science of color is well known to those skilled in the art. Withoutundue experimentation, one can use color matching techniques to identifya particular location in spherical color space. For example, one skilledin the art can use the teachings of PCT Patent PublicationWO/2004/095319 to digitally map color space using specific polymercarriers and colorants as raw material ingredients. Alternatively, onecan make small samples called plaques for visual review.

Colorants are commercially available from a number of sources well knownto those skilled in the art. Commercially available pigments are wellknown to those skilled in the art and include organic and inorganiccolorant chemistries. Commercially available dyes are well known tothose skilled in the art and include all organic chemistries. Commercialsources for pigments and dyes include multinational companies such asBASF, Bayer, Ciba-Geigy, Color-Chem International, Sun Chemical, ZhuhaiSkyhigh Chemicals, and others identified at Internet Web Sites such ashttp://www.colorpro.com/info/vendors/colorant.html andhttp://dir.yahoo.com/Business_and_Economy/Business_to_Business/Chemicals_and_Allied_Products/Pigments_and_Dyes/

Table 1 lists 61 commercially available pigment colorants in a varietyof primary and secondary colors, 54 chromatics, 5 blacks, and 2 whites.

TABLE 1 Commercial Pigment Colorants Raw Material Name CI Name FamilyCOLOR TIOXIDE R-FC6 WHITE TiO₂ PIGMENT WHITE 6 INORGANIC WHITE TIONA 696PIGMENT WHITE 6 INORGANIC WHITE REGAL 660R BLACK PIGMENT BLACK 7 ORGANICBLACK POWDER MPC CHANNEL BLACK PIGMENT BLACK 7 ORGANIC BLACK BK-5099BLACK OXIDE PIGMENT BLACK 11 INORGANIC BLACK 9880 METEOR PLUS HIGH IRPIGMENT BROWN 29 INORGANIC BLACK JET BLACK 10% FURNACE BLACK PIGMENTBLACK 7 INORGANIC BLACK HELIOGEN BLUE K7090 PIGMENT BLUE 15:3 ORGANICBLUE HELIOGEN BLUE K6903 PIGMENT BLUE B 15:1 ORGANIC BLUE 34L2000 AZUREBLUE PIGMENT BLUE 28 INORGANIC BLUE 34L2001 AMAZON BLUE PIGMENT BLUE 36INORGANIC BLUE NUBIX G-58 ULTRAMARINE PIGMENT BLUE 29 INORGANIC BLUEBLUE NUBIX C-84 ULTRAMARINE PIGMENT BLUE 29 INORGANIC BLUE BLUE NUBIXE-28 ULTRAMARINE PIGMENT BLUE 29 INORGANIC BLUE BLUE ENSIGN BLUE 214PIGMENT BLUE 28 INORGANIC BLUE HELIOGEN GREEN K-8730 PIGMENT GREEN 7ORGANIC GREEN HELIOGEN GREEN K 8605 PIGMENT GREEN 7 ORGANIC GREENCHROMIUM OXIDE GREEN PIGMENT GREEN 17 INORGANIC GREEN G-6099 CROMOPHTALORANGE GP PIGMENT ORANGE 64 ORGANIC ORANGE 2920 BRILLIANT ORANGE PIGMENTORANGE 79 ORGANIC ORANGE NOVAPERM RED F5RKA PIGMENT RED 170 ORGANIC RED225-2480 SUNBRITE PIGMENT RED 60:1 ORGANIC RED SCARLET 60:1 IRGALITE REDLCB PIGMENT RED 53:1 ORGANIC RED DCC-2782 BARIUM 2B RED PIGMENT RED 60:1ORGANIC RED LITHOL SCARLET 4451 PIGMENT RED 48:2 ORGANIC RED CROMOPHTALRED 2020 PIGMENT VIOLET 19 ORGANIC RED CROMOPHTAL MAGENTA P PIGMENT RED202 ORGANIC RED CROMOPHTAL PINK PT PIGMENT RED 122 ORGANIC RED PALIOGENRED K 3911 HD PIGMENT RED 178 ORGANIC RED CROMOPHTAL RED 2030 PIGMENTRED 254 ORGANIC RED CROMOPHTAL RED 2028 PIGMENT RED 254 ORGANIC REDCOLORTHERM RED 110M PIGMENT RED 101 INORGANIC RED COLORTHERM RED 130MPIGMENT RED 101 INORGANIC RED COLORTHERM RED 180M PIGMENT RED 101INORGANIC RED BAYFERROX 180M RED PIGMENT RED 101 INORGANIC RED R481 REDPIGMENT RED 101 INORGANIC RED R485 RED PIGMENT RED 101 INORGANIC REDR497M RED PIGMENT RED 101 INORGANIC RED CINQUASIA VIOLET RT-891-DPIGMENT VIOLET 19 ORGANIC VIOLET CROMOPHTAL VIOLET GT PIGMENT VIOLET 23ORGANIC VIOLET PREMIER VU UMV (6112) PIGMENT VIOLET 15 INORGANIC VIOLETSICOTAN BROWN K 2750 FG PIGMENT YELLOW 164 INORGANIC BROWN FERRITANFZ-1000 PIGMENT YELLOW 119 INORGANIC TAN NUBITERM Y-905K ZINC PIGMENTYELLOW 119 INORGANIC TAN FERRITE PV FAST YELLOW HG PIGMENT YELLOW 180ORGANIC YELLOW IRGALITE YELLOW WGPH PIGMENT YELLOW 168 ORGANIC YELLOW PVFAST YELLOW HGR PIGMENT YELLOW 191 ORGANIC YELLOW (11-3071) PALIOTOLYELLOW K 2270 PIGMENT YELLOW 183 ORGANIC YELLOW CROMOPHTAL YELLOW HRPAPIGMENT YELLOW 191:1 ORGANIC YELLOW CROMOPHTAL YELLOW GRP PIGMENT YELLOW95 ORGANIC YELLOW IRGALITE YELLOW WSR-P PIGMENT YELLOW 62 ORGANIC YELLOWCROMOPTHAL YELLOW 3RLP PIGMENT YELLOW 110 ORGANIC YELLOW 9766 FD & CYELLOW #6 PIGMENT YELLOW 104 ORGANIC YELLOW 9765 FD & C YELLOW #5PIGMENT YELLOW 100 ORGANIC YELLOW PALIOTOL YELLOW K 0961 (HD) PIGMENTYELLOW 138 ORGANIC YELLOW SICOPLAST YELLOW 10-0770 PIG YEL 138/PIG YEL183 ORGANIC YELLOW SICOTAN YELLOW K 2001 FG PIGMENT BROWN 24 INORGANICYELLOW SICOTAN YELLOW K 1011 PIGMENT YELLOW 53 INORGANIC YELLOWCOLORTHERM YELLOW 26 PIGMENT YELLOW 119 INORGANIC YELLOW COLORTHERM 10PIGMENT YELLOW 42 INORGANIC YELLOW V-9118 BRIGHT GOLDEN PIGMENT Brown 24INORGANIC YELLOW YELLOW

Table 2 shows 14 commercially available dyes.

TABLE 2 Commercial Dye Colorants Raw Material Name CI Name Family ColorLambdaplast Blue NL Solvent Blue 59 Anthraquinone Blue Macrolex Blue RRSolvent Blue 97 Anthraquinone Blue Granular Macrolex Green G SolventGreen 28 Anthraquinone Green Granular Macrolex Green 5B Solvent Green 3Anthraquinone Green Granular Macrolex Orange R Disperse OrangePolymethine Orange Granular 47 Macrolex Orange 3G Solvent Orange 60Perinone Orange Granular Macrolex Red EG Solvent Red 135 Perinone RedGranular Macrolex Red E2G Solvent Red 179 Perinone Red GranularThermoplast Red 454 Solvent Red 195 Anthraquinone Red Macrolex RedViolet R Disperse Violet 26 Anthraquinone Violet Granular MacrolexViolet B Solvent Violet 13 Anthraquinone Violet Granular Macrolex Violet3R Solvent Violet 36 Anthraquinone Violet Granular Key Plast Yellow 3GSolvent Yellow 93 Pyrazolone Yellow Key Plast Yellow AG Solvent YellowQuinophthalone Yellow 114

Achievement of a color match of a plaque with a desired color from thecreativity of a designer or a pre-arranged color standard such asPantone® color standards from an inventory of commercially availablecolorants is relatively straightforward for a skilled color matcher,even if a few iterations are required to satisfy the customer.

The colorant for use in the invention can have a particle size rangingfrom about 0.01 to about 10,000 micrometers, and preferably from about0.1 to about 1000 micrometers.

Frequently, the preparation of a colored plastic article does notinvolve merely color but also special effect features, such as Granite,Translucent, Pearls, Metallics, Fluorescents, Iridescents, Marbles, etc.

Non-limiting examples of such additives are commercially available fromPolyOne Corporation of Avon Lake, Ohio, USA (www.polyone.com) andmarketed under the following brands: OnColor FX colorants, PolyOnecolorants, etc.

Functional Additives

Additives to improve processing or performance of the final compound,can be added according to preferences of this skilled in the art. Forexample, functional additives can include anti-oxidants, anti-stats,acetaldehyde scavengers, lubricants, surfactants, biocides also known asanti-microbials, exfoliated nanoclays, and the like. Generally, minoramounts of such additives provide improvement of performance to thecompound during processing or in performance by the molded article aftermanufacturing. One skilled in the art without undue experimentation candetermine the appropriate concentration.

Blowing agents are sometimes desired to aid in foaming the resultingpolymer composite for density reduction, improved mold filling andreduction of sink marks in injection molding. There are two majorclasses of blowing agents endothermic and exothermic. Commercialexamples of endothermic blowing agents are products sold under the tradename Safoam by Reedy International, Hydrocerol by Clariant, Unicell Cseries by Dongjin Semichem. Commercial examples of exothermic blowingagents are Celogen series from Chemtura Corporation, Unicell D seriesfrom Dongjin Semichem. A blowing agent based on phenyltriazole chemistryis suitable for high temperature polymers like PC, PBT, glass filledpolymers. Commercial examples include Celogen 5PT from Chemtura andUnicell 5PT from Dongjin Semichem.

Plastic articles exposed to natural sunlight are exposed to ultravioletrays that can harm the color of the article. Therefore, it is customarybut not required to include ultraviolet light stabilizers in athermoplastic compound. The ultraviolet stabilizer also helps protectthe polymer resin from adverse effects arising from exposure to theultraviolet rays.

Commercially available stabilizers are well known to those skilled inthe art and include thermal stabilizers and Tinuvin brand stabilizersfrom Ciba-Geigy of Berne, Switzerland.

Table 3 shows a chart of acceptable, desirable, and preferableconcentrations of ingredients to make concentrates of the presentinvention.

TABLE 3 Acceptable Desirable Preferred Ingredient (Wt. %) Range RangeRange Carrier Resin 20-65 25-50 30-40 Colorant 30-75 40-70 50-70Optional Additives  0-40  0-30 10-20

Processing

The preparation of concentrates of the present invention is generallyuncomplicated. The concentrate can be made in batch or continuousoperations.

Mixing in a continuous process typically occurs in an extruder or acontinuous mixer that is elevated to a temperature that is sufficient tomelt the carrier resin with addition either at the head of the extruderor downstream in the extruder of the solid ingredient additives.Extruder speeds can range from about 50 to about 500 revolutions perminute (rpm), and preferably from about 100 to about 300 rpm. Typically,the output from the extruder is pelletized for later extrusion ormolding into polymeric articles.

Mixing in a batch process typically occurs in a Banbury mixer that isalso elevated to a temperature that is sufficient to melt the polymermatrix to permit addition of the solid ingredient additives. The mixingspeeds range from 60 to 1000 rpm and temperature of mixing can beambient. Also, the output from the mixer is chopped into smaller sizesfor later extrusion or molding into polymeric articles.

Subsequent extrusion or molding techniques are well known to thoseskilled in the art of thermoplastics polymer engineering. Without undueexperimentation but with such references as “Extrusion, The DefinitiveProcessing Guide and Handbook”; “Handbook of Molded Part Shrinkage andWarpage”; “Specialized Molding Techniques”; “Rotational MoldingTechnology”; and “Handbook of Mold, Tool and Die Repair Welding”, allpublished by Plastics Design Library (www.williamandrew.com), one canmake articles of any conceivable shape and appearance using compounds ofthe present invention.

In the present invention, two measures have been taken to assureminiscule pellet sizes such that 50 pellets will weigh collectively lessthan 1 gram:

(a) the extruder is equipped with a 0.047 inch (0.11938 cm) 600-holedie, also known as a mini-bead die; and, preferably

(b) strands emerging from the extruder are cut into microbeads using anunderwater pelletizer.

USEFULNESS OF THE INVENTION

As mentioned throughout, concentrates of the present invention areextremely useful for coloration of thermoplastic biofiber composites.

The thermoplastic matrix resin of the composite is selected according tothe particular use of the article being made from it. Thermoplastics arepreferred over thermosets because of recycling of waste duringmanufacture and after useful life. Commonly thermoplastics used in woodplastic composites are chosen from polyolefins and polyvinyl chloride,although other thermoplastics are capable of being selected.

“Biofiber” means a naturally-occurring fiber or particle and used in thethermoplastic composite to give the appearance of an article madesubstantially from a naturally-occurring material of which the fiber orparticle is one element. Non-limiting examples of biofibers are woodfibers, wood flour, other cellulosic fibers from bamboo, rice, and sugarcane. Other items broadly falling with this definition include groundnewsprint, magazines, books, cardboard, wood pulps (mechanical, stoneground, chemical, mechanical-chemical, bleached or unbleached, sludge,waste fines), and various agricultural wastes (rice hulls, wheat, oat,barley and oat chaff, coconut shells, peanut shells, walnut shells,straw, corn husks, corn stalks, jute, hemp, bagasse, bamboo, flax, andkenaf).

The patent and technical literature has many publications concerning themanufacture and use of thermoplastic biofiber composites. One example ofpatent literature addressing polyolefin-based biofiber composites isU.S. Pat. No. 6,680,090 (Godavarti et al.), which document isincorporated by reference herein. Among manufacturers of such productsis Andersen Corporation of Bayport, Minn.

The three factors for concentrates of the present invention are neededbecause the dispersion of color into a thermoplastic being mixed withbiofibers is exceedingly challenging. It is believed that only by use ofthe combination of pellet size, concentrate melt flow, and concentrationof colorant can one achieve the substantial color uniformity needed fora plastic article to simulate the appearance of a wood article.

With high concentration of colorant in the concentrate, one can use theconcentrate in making a colored thermoplastic biofiber composite, suchthat the concentrate comprises between about 1 and 4 weight percent ofthe weight of the total composite. With that concentration range and theconcentration of the colorant in the concentrate, one can compute thatas little as 0.30 to as much as 2.8 weight percent of colorant is usedin the thermoplastic biofiber composite, exceedingly well dispersed andsubstantially uniform in appearance in extruded or molded thermoplasticbiofiber composites.

Further explanation of the invention is found in the Examples.

Examples

Table 4 shows the sources of the ingredients used in Examples 1 and 2and Examples A-D which are formulations made in a conventional mannerbut planned to be made and sold using the manufacturing techniquesemployed for Examples 1 and 2. Table 5 shows the formulations. Table 6shows the processing conditions (settings) to make Examples 1 and 2using a Farrell Continuous Mixer connected with an extruder and anunderwater pelletizer.

The resulting pellets of Examples 1 and 2 had a microbead size andachieved the goal of being so small that at least 50 of the pellets hada mass of less than one gram. The formulations of Examples A-D wouldachieve that microbead size also if made using the microbead die and theunderwater pelletizer.

It is expected also that formulations of the melt flow index of thecarrier resin in an amount at least about 20 g/min. and a concentrationof at least 50 weight percent of colorant(s) extruded through amicrobead die into an underwater pelletizer will yield excellent colorconcentrates useful to provide coloration of polyolefin-based wood-fiberfilled composites that can be made into outdoor wood-simulation buildingmaterials.

TABLE 4 Ingredient Purpose Chemistry Commercial Source 10% FURNACE BLACK(R1170, PRINT 55) Colorant Carbon Black Columbian 9880 METEOR PLUS HIGHIR JET BLACK Colorant Carbon Black BASF ANOX BB 011/IRGANOX B225Anti-oxidant Phosphite Phenolic Ciba BAYFERROX 180M RED (D-8201)Colorant Inorganic Pigment Bayer COLORTHERM 10 Colorant InorganicPigment Lanxess COLORTHERM YELLOW 26 Colorant Inorganic Pigment LanxessCO-SPEC(R1170, PRINT 55) Colorant Carbon Black Columbian EBS WAX-TALLOWDERIVED Lubricant Ethylene-Butylene-Styrene Wax Rohm & Haas ENSIGN BLUE214 Colorant Inorganic Pigment Sheperd FERRITAN FZ-1000 ColorantInorganic Pigment Elementis LLDPE POLYMER 20 MF PELLET Carrier ResinLinear Low Density Dow Polyethylene 20 Melt Flow LLDPE POLYMER 20 MFPOWDER Carrier Resin Linear Low Density Dow Polyethylene 20 Melt FlowLUWAX AL3 Lubricant PE Wax BASF POLYCODE AO 1010 Pwdr HCINNAMAnti-oxidant Hcinnam Hphenol Ciba HPHENOL POLYCODE UV 77 Pwdr SEBACATEHALS UV-Stabilizer Sebacate HALS Ciba POLYCODE UV MPEP BZTRIAZOLE (234)UV-Stabilizer Benzotriazole Ciba PP POLYMER (H) 32 MF PELLET CarrierResin Polypropylene 32 Melt Flow Basell PP POLYMER (H) 33 MF POWDERCarrier Resin Polypropylene 33 Melt Flow Basell R-481 RED IRON OXIDEColorant Inorganic Pigment Delta R-485 RED IRON OXIDE Colorant InorganicPigment Delta R-497M RED IRON OXIDE Colorant Inorganic Pigment DeltaTINUVIN 783 FDL UV-Stabilizer Hindered Amine Ciba TIONA 696 ColorantInorganic Pigment Millennium TR28/RCL-188/TRONOX 470 Colorant InorganicPigment Millennium V-9118 BRIGHT GOLDEN YELLOW Colorant InorganicPigment Ferro

TABLE 5 Ingredients (Weight Percent) Purpose Ingredient 1 2 A B C DColorant TIONA 696 5.59 20.00 4.41 3.34 Colorant R-485 RED IRON OXIDEColorant V-9118 BRIGHT GOLDEN YELLOW Colorant CO-SPEC(R1170, PRINT 55)1.39 2.19 0.37 0.60 Colorant FERRITAN FZ-1000 17.64 22.05 Colorant R-481RED IRON OXIDE 18.23 7.17 5.03 Colorant 10% FURNACE BLACK (R1170, PRINT55) 2.62 Colorant R-497M RED IRON OXIDE 22.92 Colorant R-481 RED IRONOXIDE 8.34 Colorant TR28/RCL-188/TRONOX 470 1.96 Colorant COLORTHERM 1018.23 Colorant ENSIGN BLUE 214 2.50 Colorant 9880 METEOR PLUS HIGH IRJET BLACK 12.00 Colorant COLORTHERM YELLOW 26 26.46 Colorant BAYFERROX180M RED (D-8201) 10.03 Stabilizer POLYCODE UV MPEP BZTRIAZOLE (234)6.67 Stabilizer POLYCODE UV 77 Pwdr SEBACATE HALS 6.67 StabilizerTINUVIN 783 FDL 5.00 6.25 6.25 8.33 Anti- ANOX BB 011/IRGANOX B225 5.005.00 3.33 Oxidant Anti- POLYCODE AO 1010 Pwdr HCINNAM 2.50 3.33 OxidantHPHENOL Lubricant LUWAX AL3 3.00 3.00 2.00 Lubricant EBS WAX - TALLOWDERIVED 2.00 Carrier PP POLYMER (H) 32 MF PELLET 15.09 Carrier PPPOLYMER (H) 33 MF POWDER 35.22 Carrier LLDPE POLYMER 20 MF POWDER 16.3127.09 31.75 24.99 27.66 Carrier LLDPE POLYMER 20 MF PELLET 38.05 18.0631.75 24.99 27.66 Total 100.00 100.00 100.00 100.00 100.00 100.00Percentage Colorant 32.65 40.61 33.02 34.50 41.27 31.01 PercentageOptional Additives 13.00 14.25 16.67 2.00 8.75 13.67 Percentage of Resin54.35 45.14 50.32 63.50 49.98 55.32

TABLE 6 Processing Condition Example 1 Example 2 Target Rate (Lbs./Hr.)700 960 Feed Rate (Kg./Hr.) 360 480 FCM Revolutions per Minute (RPM) 450350 FCM Amp % 70 70 FCM Chamber Temp. (° F.) 90 90 FCM Hopper Temp. (°F.) 90 90 Orifice % Open (%) 60 60 FCM Melt Temp. (° F.) 310 320 OrificeTemp. (° F.) 250 250 Zone 1 Hopper Temp. (° F.) 175 175 Zone 2 RearTemp. (° F.) 260 260 Zone 3 Vent Temp. (° F.) 270 270 Zone 4 CenterTemp. (° F.) 280 280 Zone 5 Front Temp. (° F.) 290 290 S/C Body Temp. (°F.) 350 350 Die Temp. (° F.) 375 350 Extruder Melt Temp. (° F.) 375 350Extruder RPM 42 30 Die Plate Mini-Bead Mini-Bead Gala UnderwaterPelletizer Water 120 120 Temp. (° F.) Screen Pack (Mesh) 20 20Pelletizer RPM 4300 4600

The invention is not limited to the above embodiments. The claimsfollow.

1. (canceled)
 2. The method of claim 19, wherein the colorant comprisesa pigment, a dye, a combination of pigments, a combination of dyes, acombination of pigments and dye, a combination of pigment and dyes, or acombination of pigments and dyes.
 3. (canceled)
 4. (canceled)
 5. Themethod of claim 19, wherein the concentrate has a minimum melt flowindex of least 6 g/10 min.
 6. The method of claim 19, wherein thecolorant has a particle size ranging from about 0.01 to about 10,000micrometers.
 7. The method of claim 19, further comprising additivesproviding special features selected from the group consisting ofgranites, translucents, pearlescents, metallics, fluorescents,iridescents, marbles, and combinations thereof.
 8. The method of claim19, further comprising functional additives selected from the groupconsisting of anti-oxidants, anti-stats, acetaldehyde scavengers,blowing agents, waxes, ultraviolet light stabilizers, lubricants,surfactants, biocides, anti-microbials, exfoliated nanoclays, andcombinations thereof.
 9. The method of claim 19, wherein the amount ofcarrier resin ranges from about 20 to about 65 weight percent ofconcentrate and wherein the amount of colorant ranges from about 30 toabout 75 weight percent of the concentrate.
 10. The method of claim 19,wherein the concentrate then is subject to the steps of: (d) melt mixingthe concentrate, biofiber, and a thermoplastic to form a melt composite;and (e) shaping the melt composite into a thermoplastic biofibercomposite having coloration, wherein the ratio of concentrate to resinranges from about 1:99 to 4:96.
 11. The method of claim 10, wherein thebiofiber is selected from the group consisting of wood fibers, woodflour, bamboo fibers, rice hulls, sugar cane fiber, ground newsprint,ground magazines, ground books, ground cardboard, wood pulps, wheatchaff, oat chaff, barley chaff, oat, coconut shells, peanut shells,walnut shells, straw, corn husks, corn stalks, jute, hemp, bagasse,bamboo, flax, kenaf, and combinations thereof.
 12. The method of claim10, wherein the thermoplastic resin matrix is selected from the groupconsisting of polyolefins and polyvinyl chloride.
 13. The method ofclaim 7, wherein the concentrate then is subject to the steps of: (d)melt mixing the concentrate, biofiber, and a thermoplastic to form amelt composite; and (e) shaping the melt composite into a thermoplasticbiofiber composite having coloration, wherein the ratio of concentrateto resin ranges from about 1:99 to 4:96.
 14. The method of claim 13,wherein the biofiber is selected from the group consisting of woodfibers, wood flour, bamboo fibers, rice hulls, sugar cane fiber, groundnewsprint, ground magazines, ground books, ground cardboard, wood pulps,wheat chaff, oat chaff, barley chaff, oat, coconut shells, peanutshells, walnut shells, straw, corn husks, corn stalks, jute, hemp,bagasse, bamboo, flax, kenaf, and combinations thereof.
 15. The methodof claim 13, wherein the thermoplastic resin matrix is selected from thegroup consisting of polyolefins and polyvinyl chloride.
 16. The methodof claim 8, wherein the concentrate then is subject to the steps of: (d)melt mixing the concentrate, biofiber, and a thermoplastic to form amelt composite; and (e) shaping the melt composite into a thermoplasticbiofiber composite having coloration, wherein the ratio of concentrateto resin ranges from about 1:99 to 4:96.
 17. The method of claim 16,wherein the biofiber is selected from the group consisting of woodfibers, wood flour, bamboo fibers, rice hulls, sugar cane fiber, groundnewsprint, ground magazines, ground books, ground cardboard, wood pulps,wheat chaff, oat chaff, barley chaff, oat, coconut shells, peanutshells, walnut shells, straw, corn husks, corn stalks, jute, hemp,bagasse, bamboo, flax, kenaf, and combinations thereof.
 18. The methodof claim 16, wherein the thermoplastic resin matrix is selected from thegroup consisting of polyolefins and polyvinyl chloride.
 19. A method ofmaking a colorant concentrate for a thermoplastic biofiber composite,comprising the steps of: (a) melt mixing carrier resin comprisinglow-density polyethylene, linear-low-density polyethylene, orpolypropylene, colorant, and any optional additives in a chamber to forma melt concentrate; (b) extruding the melt concentrate through amini-bead die; and (c) pelletizing the melt concentrate under water toform pellets of a shape of microbeads such that at least 50 pellets havea total mass of less than one gram, wherein (1) melt flow index of theconcentrate exceeds at least 4 g/10 min. using ASTM D-1238 and (2)weight percent of colorant exceeds at least 30 weight percent of theweight of the concentrate.
 20. The method of claim 19, wherein theconcentrate then is subject to the steps of: (d) melt mixing theconcentrate, biofiber, and a thermoplastic to form a melt composite; and(e) shaping the melt composite into a thermoplastic biofiber compositehaving coloration.